Dust collecting bag



part 13 of the shaking apparatus.

Patented Aug. 7, 1934 UNITED STATES A PATENT OFFICE 4 Claims.

This invention relates to dust collecting apparatus, and particularly to improvements in the filter bags, which are used in connection with the operation of such equipment. The bags in question comprise long tubular members, which extend vertically in the collector and which filter the air, as it passes therethrough. The air usually enters the lower end of the bags at a velocity of about five thousand feet per minute. At this speed, the abrasive action is so great that the normal life of the bags is only about three months. Obviously, therefore, the replacement expense in connection with a dust collector is a large factor in the operation thereof.

A further consideration in connection with the operation of dust collecting equipment is the fact that the dust is usually removed by reversing the direction of the air current through the bags and simultaneously subjecting them to a shaking movement. The shaking has been accomplished by lowering the upper end of the bag, while holding the lower end stationary, thus allowing it to collapse and then suddenly stretching it. This has been satisfactory for cleaning the middle and upper portions, but not for the lower portions, for the relative movement of the lower portion with reference to the fixed support is not as great as that which occurs in the upper portion.

An object of the present invention therefore, is to improve the bag construction so as to materially increase the life thereof and to effect a thorough cleansing throughout the entire length thereof. In this connection, my invention contemplates a bag construction, which will accomplish these objects without necessitating any modification in the construction of the bag supports or in the shaking apparatus. Thus, the bags can be used to replace those, which are in use on existing equipment.

Referring now to the drawing, Figure 1 is an elevation partly in section of a filter bag embodying my invention; Fig. 2 is a diagrammatic view illustrating the movement of the dust laden air, and Fig. 3 is a similar view illustrating the movement of the air in a reverse direction, while the bag is being shaken.

Since my invention may be used in connection with present forms of dust collecting equip ment, I have merely illustrated the bag 10, as being attached at 11 adjacent the bottom thereof to a stationary support 12, and at the top to a The bag has the usual cylindrical construction which is open at the bottom for the admission of air and which is closed at the top so as to force the dust laden air to filter through the'bag as it moves longitudinally thereof. In order to obtain the necessary porosity and yet be sufficiently flexible for movement during the shaking operation, the bags have been made of cotton fabric, which has been sewn to the desired form. I utilize the same material for making the bag, but I provide a protecting medium adjacent the inlet end thereof for reducing the abrasive action and thereby lengthening the life of the bag.

The bag protecting device which I have invented comprises preferably a tubular member 15 which may be in the form of an inverted truncated cone, which is attached to the bag at a point above the bottom thereof, and which is disposed inside the bag and preferably projects below the bottom thereof. This member may be made of relatively heavy canvas, which is formed to the desired shape, and is then sewed onto the bag, as is indicated at 16. A weighted ring 17 is then attached to the lowermost end of the member for holding it in vertical position and imparting an added jerk to it at each shaking movement thereof. At the point where the canvas member is attached to the bag, the velocity is reduced to approximately 1500 feet per minute, so that the abrasive action is materially lessened. Furthermore, the relatively heavy canvas absorbs the abrasive stresses and quickly becomes covered with a layer of dust which acts as a cushion for the relatively heavy particles of material that are carried into the collector with the current of air. A further consideration in connection with this arrangement is the fact that the conical form of the mem ber 15 still leaves the lower portion of the bag, and particularly that part between the point of attachment 16 and the support 11 free to filter air which impinges thereagainst. Thus, the efficiency of the bag is not impaired, for the filtering area remains substantially the same.

An important advantage of my invention is the fact that it may be applied to present forms of bag construction without necessitating a modification of the dust collecting equipment. A further important advantage is the fact that the life of the bag is very materially increased without any substantial increase in the cos thereof.

I therefore claim: 1. A dust collector filter bag having a flexible tubular member attached thereto intermediate tector in the form of a sleeve disposed therein and adjacent the inlet end thereof, and a weight on the protector beyond the end of the bag.

4. In combination, a cylindrical filter bag of relatively light fabric material, the bag being disposed vertically and being substantially cylindrical in shape and open at the bottom thereof, a protector in the form of an inverted truncated cone of relatively heavy fabric, the protector beingattached to the bag above the bottom thereof and projecting beyond the lower end thereof, and a weighted ring attached to the protector adjacent the lower end thereof.

MICHAEL A. EIBEN. 

